The present invention relates to a drying apparatus using combined microwave heating and air flow for drying food products rapidly while maintaining their flavor and providing them with improved shelf life.
Conventional methods for accomplishing the drying of foods include air-drying, freeze-drying, microwave heating, etc. However, the use of any of these techniques by itself has certain disadvantages. Such disadvantages include the requirement of much time to achieve the desired drying, deterioration of the quality of the food product, and high operating costs.
For instance, the microwave heating method operates on the principle of causing heating on the basis of a dielectric loss in the material being heated, and is characterized by the inside of the material being heated as well as the outside, which is in contrast to the case of the ordinary heating techniques which heat from the outside of the material. However, the microwave heating technique also results in the occurrence of heat degeneration of the food product as the temperature increases, and when microwave heating is employed alone, there is the drawback of the operating cost being too high.
Conversely, in the case of using only the air-drying method to reduce the moisture content of food products, a big problem is that there is poor evaporation of the moisture from the internal regions of the food material. For this reason, a long time is required to accomplish the desired degree of drying, and the productivity is low.
Accordingly, an object of the present invention is to provide an arrangement for drying food products with minimal heat degradation thereof.